exact rational re-evaluation of 3030 sample patterns against the C values: mismatches = 0
(E1) patterns with value 6: exactly the 39 distinct hyperplane windows H(a,c) (13 directions a, c in Z/3): OK
(E2) gluing: unique successor H(a, c - a_i) and unique predecessor H(a, c + a_i) in each axis i: OK
     the 39 windows are permuted by the 48 cube symmetries: OK
stacked grid on (Z/3)^3, A on the plane y_1 = 0: appearances = 162  concentration = 6
hyperplane grids a.y = c (mod 3), 3 | n_i when a_i != 0, n_i arbitrary (1,2,4) when a_i = 0: concentration 6 in all 156 tested cases
for each of the 13 a: exactly 18 directions v with a.v != 0 (mod 3): OK
second largest value = 6 - 1079/90720 (claimed 1079/90720: True )
ALL 3D POST-CHECKS PASSED
